(1) Field of the Invention
The invention relates to a 3D laser leveler, and more particularly to a spatial level extension apparatus.
(2) Description of the Prior Art
In the construction industry, drawing or determining a distant horizontal or vertical line from a reference line is sometimes not easy to achieve in one step, especially for those desired lines located at different elevations. Conventional methods for carrying out the line-drawing or line-determination operation can be performed by utilizing rulers, ink-string boxes, levelers, and so on as are well well-known in the art.
During the operation, a reference line is first selected. The reference line can be corner lines, fence lines, or any horizontal or vertical line defined by a square-beam leveler or other device. Then, a first extension line of the reference line can be defined by using rulers or an ink-string box. When using a first ruler to draw the first extension line, one side of the first ruler is used to be aligned with the reference line and the first extension line can be formed by using a second ruler as an extension of the first ruler to elongate the reference line.
The conventional ink-string box comprises a box for carrying a roller at one half and ink at another half. The roller is pivoted on top of the box, and an extension string rolled around the roller. The extension string has a free end that is pulled over the ink and away from the box. While applying the ink-string box to draw the first extension line of a reference line, the string is pulled out from the roller and mixed with the ink during the pulling operation, then aligned with the reference line, and then the first extension line is formed by flipping the extended inked string to drop the ink lengthwise.
After the first extension line is determined, additional extension lines may still be needed for extending the first extension line to another direction or to another elevation, depending upon where the desired lines are located. As long as all extension lines are defined, the-desired line can be determined by a ruler, an ink-string box, or any tool that can be used to form a straight line.
Obviously, the aforesaid conventional methods that determine a desired line by using extension lines may sometimes be tedious and difficult to achieve accurately, and may be subject to human error.
Thus, there remains a need for a line-extension tool that provides accurate extension ability and is effective for use in distances of all ranges, yet is easy to use and can be used quickly and efficiently.